Radiographic apparatus has various types of forms to acquire a radioscopic image through irradiating a subject with radiation. For instance, examples of the radiographic apparatus include one that allows generation of a clear radioscopic image through superimposing strip images. Such a method of acquiring an image is called slit imaging, and is well known (see, for example, Patent Literture 1).
Now, description will be given hereinafter of a configuration in such radiographic apparatus. As shown in FIG. 13, the conventional radiography apparatus 51 includes a top board 52 for supporting a subject M placed thereon, a radiation source 53 above the top board 52, and a radiation detector (FPD) 54 below the top board 52. The radiation source 53 and the FPD 54 are movable along a body axis direction A of the subject M. The radiation source 53 has a collimator 53a attached thereto, whereby radiation is collimated to generate radiation beams in a fan shape.
Firstly, in order to acquire a radioscopy image in the radiographic apparatus 51, the radiation source 53 and the FPD54 move synchronously while radiation beams are emitted intermittently. Here, as shown in FIG. 14, the radiation source 53 and the FPD 54 move along the body axis direction A of the subject M relative to the top board 52 while maintaining a relative positional relationship therebetween. Radiation beams transmit through the subject M and are detected with the FPD 54 in every irradiation therewith. Accordingly, a strip image is generated that extends in a body side direction S of the subject M. in every detection of radiation beams with the FPD 54.
Synchronous movement of the radiation source 53 and the FPD 54 causes deviation in a relative positional relationship of the radiation source 53, the FPD 54, and the subject M along the body axis direction A of the subject M. That is, each strip image has a different site of the subject M falling thereon.
Upon completion of irradiation with radiation beams, the strip images are superimposed one another while shifting, whereby a single radioscopic image is generated.
As is apparent from FIG. 14, radiation beams enter into the FPD 54 at an appropriately right angle. Accordingly, a clearer image may be acquired. Radiation emitted from the radiation source is divided into direct radiation linearly entering into the FPD 54, and indirect radiation entering into the FPD 54 having a modified traveling direction due to the subject M or the top board 52. Indirect radiation is obstructive to generation of a clear radioscopic image. Incidence of radiation into the FPD 54 at an appropriately right angle may realize elimination of the influence of indirect radiation. The radioscopic image is conventionally generated using only incident radiation into the FPD 54 at an appropriately right angle. Consequently, a clearer radioscopic image may be acquired under no influence of indirect radiation.
As above, a clearer radioscopic image may be acquired using only incident radiation into the FPD 54 at an appropriately right angle. On the other hand, however, only a small range of the subject M may be imaged with such radiation beams, and radiation beams are not usable for diagnosis as they are. Accordingly, stripe images are acquired through imaging two or more times and are superimposed for acquiring a radioscopic image having a fluoroscopy image of the subject M falling thereon in a wide range.
[Patent Literature 1]
Japanese Patent Publication No. 2008-219428